Frequency reducing system



Augo 3, A1937., c. P. sTocKER 2,088513 FREQUENCY RTDUC ING SYSTEM Filed June 3, 1955 .uNi'reo jsTATEs'A:

, .mais li'lllQUiiNcYmucmu srs'rnis Cineman l. Stocker, main. Ohio,

one-half to E. sl. Heavens. Elyria.

animan runes, 193.5, sensi Na. usss szcisinu. (ci. 11a-ssi) This invention relates to frequency reducing systems and more particularly to static frequency reducing systems employing a non-linear imped lance element.

In general, if acurrent pf a fundamental fre-- quency in flowing through a circuit resonant to this frequency causesto be produced in this circuit a current of an harmonic frequency of the fundamental frequency, then if this harmonic frequency be supplied to the circuit, a current of the fundamental frequency may be maintained. A necessary condition for this is that a current of the fundamental frequency be started flowing in .the circuit. y 4

An object of this in ventionis to provide an improved and more reliable starting arrangement for starting a current of the fundamental frequency in this type of circuit. q v

In addition, inv circuits of this type the power output is not only relatively low but the range I' of load or power output -is lover. Thus. ifv the eircuitoperates satisfactorily 'at m11 10nd it. is

apt to become unstable at no load and cease to operate. If the circuit is stable atv no load'the maximum power outputds greatly reduced;

It is a further object of this invention to increase the maximum power output of such a circuit and .to increase the range of loador power output and at the saine time to make the circuit less sensitive to abrupt'changes i load. I

A feature of the invention re vto the auto.-

matic starting 'arrangement for automatically` starting a current of the fundamental frequency flowing in the circuit when a current of the'harmonic frequency of the fimdamental frequency n is applied to the circuit.

" In accordancewith another feature of this in- 50 establishing asdirect current flux and for causing the direct current flux to collapse and induce a `voltaire in the oscillating circuit'of my frequency reducing system and thereby cause a current to` 9 new in 'the said oscillating circuit independent 55 of the alternating current supplied by the source portion of 1; impressed upon of alternating current to start free oscillation in the said oscillating circuit at the said fundamental frequency and at the harmonicstherepf.

A further object of my invention is the-provision ofv a frequency reducing arrangement adapted to be energized by a source of alternating current andv to be started in operation by a source of direct current.

Another object of my invention is to provide forgiving stability of operation throughout a widel range of load conditions.

It is also an object of my invention to provide flux, which when the rectied circuit is interrupted, collapses and causes acurrent to iiow in the said oscillating circuit independent of the alternating current supplied by the surce of al-V ternating current to start free oscillating in the said oscillating circuit frequency and at the harmonics thereof. n

It isalso'ian object of my invention to provide for causing the starting means to be repeatedly operated until the said free oscillations started.

l It is a further object of my invention` for delaying the operation of the flux' means and establishing a relatively large amount of nur to insure the positive starting of the said oscillations.

A further object of my invention is the provision of a stabilizing means for shunting a portion of the oscillating circuit vto by-pass a portion of the` oscillating current from fthe said shunted the oscillating circuittowards giving a rectied circuit for establishing' a direct currenty n at the said fundamental stability in the output source throughout a wide range of load conditions.

A further object of my invention is to provide for operating the `shuntingand stabilizing means substantially at or near a part of the shunting or stabilizing means.

A further object of my invention is to increase the effective capacity of the oscillating circuit the knee of the maar L -netization curve of ythe iron core which comprises by` utilizing a transformer to step up the voltage rangement stabilizes the oscillating circuit and also permits more power to be obtained from a given set of inductance coils and condensers.

A still further ob'ject of my invention is to provide output means connected in circuit relation'with the oscillating circuit, so that the voltage across-the output means is a combination of the voltage across the condenser and the inductance; or a portion of the voltage across said des Another object of my invention is to provide the condenser, wherein the ar not so limited, it w111 for delivering a substantially constant output voltage of reduced frequency for relatively wide variations of the input voltage.

These and other objects and features of the invention may be more readily understood from the following description-of several embodiments of the invention when read with reference to the attached drawing in which:

Fig. 1 shows a-simple circuit arrangement employing my new starting arrangement;

Fig. 2 shows a simplified form of the stabilizi arrangement applied to Fig. 1:

Fig. 3 shows the preferred embodiment of the invention employing the improved starting arrangement, the stabilizing arrangement, the automatic starting feature, and means for controlling the higher frequencies in the -output current and Fig. 4 shows a modified starting arrangement applied to a circuit similar to the one shown in Fig. 3.

While it is understood that the invention is be described with reference to several specific embodiments thereof which are ysuitable for reducing the frequency current from a commercial alternating current power supply system so that it will be suitable for supplying low frequency current to a signalling system, such as, ringing current for a telephone system.

`-Similar parts of the different gures are designated with `the same reference numerals.

Referring now to the drawing, I represents a vsource of alternating current which for the purpose of illustration will be assumed to be of a frequency of 60-cycles per second. However, it is to be understood that any other suitable frequency may be used. This source of power I may be a transformer winding, a power line or a generator which is capable of delivering the required power to the circuit comprising inductance 2 and condenser l. Again by way of example it will be assumed that this circuit is tuned so as to oscillate freely at a frequency of -cycles per second. It is to be understood that this circuit may be tune'd so that it will oscillate freely at any other suitable frequency. v

Inductance 2 is wound upon a saturablc core so its inductance varies in accordance with the current through it or the voltage across it and thus constitutes a nonlinear impedance element. The circuit comprising inductance 2 and condenser 3 will therefore distort the wave form of the current through it and thus generate currents of harmonic frequencies.

If now switch 9 is closed to connect source I to this circuit and a 20-cycle current started iiow ing in the circuit a 3rd harmonic or 60-cycle current will be generated due to distortion of the 20-cyc1e wave form and a current supplied from the SO-cycle source will maintain the 20-cycle curi-ent flowing in the circuit. Thus, when the oscillating circuit is vonce set in operation, the alternating current from the alternating current supply source I keeps up the said harmonics that has a frequency that is equal to the frequency of the said source of alternating current, thereby causing electrical energy to be delivered to the oscillating circuit for sustaining the oscillations and for delivering power tothe output circuit. In fact some 20-cycle power may be taken from the circuit either from leads connected across `condenser l or from leads 'I connected across inductance 2. .It is to be noted that when the circuit is tuned to 2li-cycles the reactance of condenser I is much lower to 60cycles and higher Y 20-cycle current in this circuit.

frequencies than is the reactanc'e of inductance 2'so that there will be much less (iO-cycle and higher frequency current flowing in output 6 than in output l. e,

In case,the 20-cycle output current is to be used to supply ringing current to a telephone sys. tem the audible ring back tone may be readily adjusted by using different percentages of the two output currents from leads 6 and 1 or by connecting a.v small auxiliary inductance in sexies vwith condenser 3 and connecting the output circuit across the series combination of condenser l and auxiliary inductance. -This arrangement will b described more in detail with reference to Fig. 3. In Figure 2, these different percentages are obtained by connecting the tap leads la to the winding of the inductance 2. This means that when the output source is taken from the lower lead and one of the tap leads "Ia, the con `denser 3 is connected in series with a portion of the vwinding of the inductance 2. By reason of this arrangement, the'tapped-portion of the winding of the inductance 2 causes the high frequency current to modify' the wave form of the fundamental oscillating current. In other words, at low frequencies, the tapped portion of the winding 2 is ineffective to modify the wave form of the fundamental oscillating current, but becomes effective at higher frequencies to modify the wave form of the fundamental load output current to supply the audible ring back tone of a telephone system. i

There are various ways of starting an oscillating current, which by way of example can be For example, under certain conditions this oscillating current may be started by closing switch 9. This method however is not very effective since the oscillating b current is started only once for five or moreclosux-es of switch 9.

l A more effective way of starting the oscillations s to 50% to 75% is broken.

I have discovered that if this short circuit or starting circuit includesa source of direct current 5 the'oscillating current will start substantially every time switch 4 is opened. Furthermore this arrangement is capable of starting the oscillating current substantially all the time under conditions where the oscillating current may be started only with the greatest difficulty by other means.

The direct current source 5 may be any suitable source of direct current such as a primary battery. a storage battery, generator or power line. This source miay also comprise a unilateral or a symmetric'al conducting device such as a rectifier connected across inductance 2 or across a part of inductance 2. Such an arrangement is shown in I Fig. 3 where rectifier I B is connected across a part of inductance 2. This device may be connected in a starting circuit which includes a separate winding on the core of inductance 2 as shown in Fig. 2.

Fig. 3 also shows an automatic switching arrangement for interrupting the circuit of rectifier Il. When switch 9 is closed alternating current from source I flows through inductance 2 lower winding of relay iI2 and transformer 8. Both alternating current and direct current flow through the right portion ofinductance 2, upper winding of relay I2, break contacts 4, of relay Then when the direct current has built up to the "operate value of relay and interrupt the circuit through rectifier I and start an oscillating current owingthrough the lo'tuned circuit which circuit includes the vlower source I, switch 9, and inductance 2. Relay I2 is held operated by the oscillating current flowing in this circuit. `When oscillations are stopped relay I2 will release and clo'se the circuit of winding of relay I2, winding of vtransformer I,-

,osasis substantially no flux in the core of relay I2.v

I2 this relay will operate rectifier I5 whereupon the above described action isrepeated. This particular circuitvarrange ment has the advantage that it insures that the direct current will build up to a dennite value sufficient to insure the starting. of the oscil- -lating current before contacts 4 are opened. Con- .denser II and choke I0 are provided to suppress radio frequency current which may cause radio interference.

Incase there is some trouble in this circuit or in the output circuit which preventsv the oscillating current from starting, relay I2 will operate and release as described above.Q This wears the cuit will olcillte satisfwrily to limit the. current at no load so that contacts I and may cause the rectifier I5, inductance 2, relay I2, 'or other apparatus to become hot and damaged. lTo prevent this any suitable protective device such as a fuse or heat coil I6 may be connected in any 'of the circuits. The preferred arrangement shown in Fig. 3 comprises a heat coil I6 which will allow the normal starting current to flow in thel starting circuit `momentarily to operate relay I2 and start'the oscillating current without operating heat coil IB. However, if this circuit is repeatedly closed and opened, heat coil- I6 will operate to open the which may be connected to any suitable alarm or trouble'indicatin'g circuit (not shown).

Fig. 4 shows another method of automatically controlling the circuit of the rectifier. Here vrectifier I5 is connected across supply I and part of inductance 2. In this'circuit' relay I2 operates on the alternating current flowing through its` .winding 'I'he operation ofA relay I2 in Fig. 4 should be retarded to give the direct current flowing through inductance 2`sufilcient time to buildup to a value sufficient to insure thestart'- ing thev oscillations vwhen contacts tare opened. As in the circuit shown in Fig. 3 the condenser II and choke Ill shown in Fig. 4 are provided to ysuppress radio frequency currents which may cause interference.

operating circuit and close a circuit to-v line "Il When a source of direct current, such as'a rectier, is includedl in the starting circuit, con- 60' denser 3 maybeicoupled to the oscillating circuit as shown in Fig. 3 through a transformer such as transformer 8 of Figs. 3 and 4. 'I'his arrangement stabilizes the circuitand permits more power to be obtained from a given set `of coils and con 65 densers. This transformer may also serve as an output transformer.

'I 'he exact manner in whichthis circuit operates is not f ullygunderstood but there ap rs to be at least three different factors which contribute to the improved operation of this circuit.'

i By coupnng the condenser to the circmttnrbush i a transformer, the condenser may be operated ait` I a higher voltage and 'at the same time by normally operating the core of the transformer near the knee of the saturation curve the peak voltages this manner coil `lstabilise the plied to condenser 3 noi` Fig. 2 so that the relatively wide lfluctuations of the 3 applicdtothecondenserduetosursesandtransient currents are limited.` This arrangement permits a-given condenser to' be operated more effectively and at the same time have its apparent impedance in the oscillating circuit greatly. reduced. For a given size of condenser and in-` ductance this arrangement permits considerably more power to be taken from the circuit before theoscillationscease.

In addition this transformer l appears t0 v1o circuit and to make it less affected by sudden changes in the connected load. In general, if the constants of the usual circuit such as showninl'lg. 1 areadiust'ed sothat the circuit-will oscillate satisfactorily at no load, it is impossible totake appreciable power from the circuit before the oscillations cease. If on the other hand the constants are adjusted so the cir- I l when appreciable load is taken from the circuit, then the circuit beomes unstable and usually changes the frequency of 'oscillation when the load is removed. It has been found that the circuit may be stabilized by adding resistance inseries with inductance 2.and condenser I. 'Ihis resistance appears the value of the inductance is not reduced to such a low value that it resonates with condenser 3 at -a higher frequency. This vresistance however reduces the power that the circuit will deliver before the oscillations or the oscillating current stops. Of course the resistance may benvaried with load, such as by including a ballast lampin the oscillating circuit, but even with such an arrangement it is impossible to vary the resistance' as rapidly as the load can change. So this .arrangement while permitting some increase in power tobetaken from the circuit does not stabilize the circultand make it insensitive to change in load.

In'order to understand more fully some of the factors contributingv to the stabilizing action of y transformer l, reference may be had to Fig. 2 which shows a simplined circuit arrangement of Fig. 3. Here transformer 8 is replaced by coil I which represents the inductance of transformer It 'is to be noted thatin the circuit Vshown in Fig. 2 there is no step up in the voltage apis there an apparent increase inthe capacity of this condenser. However, by adjusting the constants. ofthe circuit of circuit is stable at full load and adjustingA the turns'of coil 8 so that the' liron is. just about saturated (near or on the kn'e of the magnetization curve) ,then as the load is removed and the current through the circuit tends to increase the voltage across the various ele-A ments also tends to increase. This increase 'in voltage across condenser 3 and coil 8 will reduce, the impedance of coil I which in turn tends to reduce Aand limit the voltage and current in.- creaserin thev circuit astheload is reduced. -In

I tends to prevent or reduce any increase :inthe oscillating current as the load is removed and this tends 'to lstabilize the operation of this system. I find that this arrangement -gives excellent operation from the standpoint of load stability throughout a. relatively widerange of load conditions. It also gives excellent voltage regulation from the standpoint of maintaining a substantially constant output voltagefor input voltage. i This is true because the iron` of the transformer I is operated at or near the kneeof the imag- 75 csf cuits and tomake the netization curve and gives very critical control. The inductance of the lcoil B may be of such a value that it also will resonate with the condenser l either at the fundamental frequency or at an harmonic or a lower harmonic of the funda'- mental frequency of the inductance 2 and the condenser 3. This means that the oscillating circuit including the inductance of the coil orV transformer 8 andthe condenser 3 may be adjusted to oscillate freely at a fundamental -frequencyv and produce harmonics wherein one of the said harmonics of said oscillating circuit is of a frequency equal to the fundamental frequency of the oscillating circuit including the in ductance 2 and' the condenser 3. By this arrangement the supply leads 6 may give a frequency equal to the fundamental frequency of said first mentioned oscillating circuit, as well as give a frequency equal to the fundamental frequency of the said second mentioned oscillating circuit. l

Coil 8 may provide a further 4stabilizing action in this circuit. 'Ihe inductance of coil 8 may be of such a value that it also will resonate with condenser 3 at either the fundamental frequency or an harmonic of the fundamental frequency of inductance 2 and condenser 3. In this case the stabilizing action is the result of tending' tov make the amplitude of the oscillating currentv more independent of the load current.` This action of the circuit employing coil or transformer l may be somewhat like the action of the constant current circuits described on pages 76 to 82. of "Alternating Current Phenomena by Steinmetz, third edition 1900 published by McGraw Publishing Co. or similar to the Monocyclic Networ described in an article entitled Constant Current D-C Transmission by C. H. Willis, B. D.

Bedford, and F. R.. Elder published in Electrical Engineering Journal on page`l02, vol. 54, No. 1

(January 1935).

Again, when the load is connected to a winding on coil or transformer 8, this transformer may be thought of as tending to isolate the two ciroscillating circuit independent of changes in the load circuit. In this respect this arrangement appears to operate in a manner somewhat similar to the manner of operation in certain of the circuits used to stabi- A lize `the frequency of vacuum tube oscillators which are described by F. B. Llewellyn in an article entitled "Constant Frequency Oscillators and i published in I. R. E., vol. 19 pp. 2 063--2094` for December, i931.

Also we may consider the'coil or transformer 8 00 l as functioninggto by-pass as a shunting device for stabilizing the oscillations of the oscillating circuit. When considering the coil or transformer 8 as a shunting device, we may consider the coil or the transformer a portion of the oscillating current from the said shunted portion of the said oscillating circuit. -In this manner, the coil or transformer derby-passes such portion of the oscillating current as to produce stability-A of the output circuit -throughout a relatively wide range of load conditigns, andthroughout a relatively wide range of `the input voltage. Thus, the voltage across the output leads may be maintained substantially constant for relatively wide 7o variations of the input voltage.

Thus coil or transformer l appears to have a three fold stabilizing action which comprises (1). matching or adjusting the impedances of various circuits and elements, -(2) tendingeto prevent u changes in theaafipiitude of .the oscillating, cira,ose,e1a cuit and (3) making the amplitude of the oscillating current more independent of the load connected to the circuit.

Referring again to Fis. 3, an additional small variable inductance I8 is connected in series with condenser 3 and provides a simple and effective means for controlling the amount oi.' high frequency current in the output circuit. This may be used for an audible ringing signal when this arrangement is used to supply ringing current for a telephone system. This additional or auxe -iliary inductance may be similarly-connected in Fig. 4 and operates in the same manner as described with reference to Fig. 1. -In this case contact 9 may be automatically controlled by the illustrated relay either directly or indirectly by ringing'keys or relays incord circuits or maehineswitching circuits of the telephone system.

In the development of my invention, tests were made using the regular 120 volt BO-cycle commercial power supply. While. it is understood that the values and sizes of the various elements lo1' the circuit of Fig. 3 depend uponv the power,

voltage and current which the circuit must supply as well as upon the supply voltage, I have found, that in a particular embodiment of the invention, a 'circuit having an inductance 2 wound on an iron core having a cross-sectional area of 2.25 square inches, a transformer 8 having an iron core with a cross-sectional area of 4.5 square inches, and condenser 3 having a capacity of 20 mid. appears to operate satisfactorily. It is interesting to note that in a circuit as per Fig. 1, when using inductance 2 with 2.25 square inches of iron in the vcore and .a capacity of 20 mfd., the maximum power output at 20-cyc1es seems to be in the order of 25 watts with very poor output voltage regulation. In fact, it is not unusual for the output voltage to vary as much as 40% between no load and full load of 25 watts.

With my invention as depicted in Fig. 3 and inductance 2 and transformer 8 having the cross sectional areas mentioned above and using 20 mfd. capacity as before, I have had no difficulty in taking more than 1/8 horse-power oi' 20-cycle power from this circuit. Also the output voltage regulation is much improved having a total voltage variation, at terminals S, of only 7% between no load and full load of 1A; H. P. As used in this-specification, the terms fundamental frequency or fundamental current refer to the resonant frequency or a current having the resonant frequency of the oscillating circuit of the frequency reducing system. The terms harmonic frequency or harmonic current refer to frequencies or to current having frequencies which are multiples of the fundamental frequency. For example, the third harmonic current or voltage has a frequency which is three times the frequency of the fundamental current or voltage.

In the description and inthe claims, the oscillating circuit is characterized as being adapted to oscillate freely at a fundamental frequency and at the harmonics of the said fundamental frequency. Also, the starting arrangement, described and claimed in the application, is characterized as being adapted tostart free oscillations in the oscillating circuit at the fundamental frequency and at the harmonics thereof. It is further. characterized in the description and in the claims that the alternating current from the supply source, which energizes the oscillatlng circuit. keeps up the said harmonic that has a .frequency equal vto the frequency ofthe said colinear impedance accasis source of alternating current'and causes com'y tinued oscillations of the fundamental current at the fundamental frequency in the oscillating'circuit. By this characterisstion, I mean that,` when the circuit is started to oscillate, thereis present, in the cirqiit, a fundamental current" 'f'aand harmonic curren ferred, however, that the oscillating circuit' lis tuned to oscillate freely at the harmonic frequencies.- This is not thecase. The oscillating circuit lis tuned to omillate freely at the fundamental frequency, which when the fundamental oscillation takes place, there is present in the circuit both a "fundamental curren and harmonic current",- summarizing, it is to be pointed out that a frequency reducing arrangement em- ?i bodying the features of my invention, as shown and described' herein, actually produces-a current having a reduced frequency, and for this reason'it is to be clearly understood that' the principle or theory of operation of myl invention as explained 'f-ll herein, is to be construed as being merely ex.- planatory. The foregoing description of the principle of operation constitutes the best known theoretical explanation of its operation. Therefore', in no sense shall the theory of operation herein described he construed as a limitation upon the claims, as there may be other expiana tions of its theory or principle of operation.

Althoughl I have described my invention with a certain degree of -particularity, it is understood that the present disclosure has been made only by way o'f example and that' numerous changes in the details of constructionv and the i combination ,and arrangement of parts may be resortedto without departing .from the spirit and What is claimed is: v l. A frequency reducing nt adapted 40 to beenergired by a source of alternating cur-` the fundamental frequency is less than the frequency of the said source of alternating current and wherein the frequency of one of `said harmonics is equalto the frequency ofthe said source of alternating current, means for con- ,352 nccung the said escalating 'circuit in circuit re- Jlation with the said source of alternating current to keep up the said harmonic that has a frequency equal to the frequency of the said source of alternating current and to cause con- `\:1 u" at the fundamental frequencyin the oscillating circuit, and means for nonelement in circuit relation-with 'thesaidsourcecfdirectcurrenttoestablis'ha direct current' flux 'and Ifor disconnecting the tien with the said source of direct currenttc cause thc saiddirect current flux to collapse and induce a voltage in the nonf-linear impedance ifstart free-oscillationsY in the oscillating cirfundamental frequency and at q cuit at the said harmonics thereof. -v A frequency reducing arrangement-adapted t'cbev energized hy 'a source o f alternating current comprising, in combination, an oscillating l circuit including a non-linear impedance element and adapted to oscillate freely at a fundamental frequency and produce harmonics of the It is not t0 be 1li-- 3.'Afrequencyreducing @l the scope of the inventionv as claimed.

fued oscillations of the fimadrnentai. current 1 non-lineariimpedance element fromcircuit relasaid fundamental frequency, wherein the fundamental frequency is less the said source of alternating in the frequency of one of equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuit in ci, source of alternating current to keep up the said harmonic that has a frequency-equal to the frequency of the' said source of valternating current yand to cause continued oscillations of 'mental current at the fundamental frequency in the oscillatingl circuit. an asymmetrical impedanc'e element, means for connecting the nonimpedance element in circuit relation with the said asymmetrical impedance element to es- 'a direct current ilux and for disconnectrcuit relation with the said thanthe frequency of current land wheresaid harmonics is ingthe said non-linear impedance element from i circuit relation with thesaid asymmetrical impedanceelementtocausethesald directcurrent ux to collapse and induce ayoltage in the nonlinear impedance to start freeoscillations in the oscillating circuit at the said fundamental frequency and at the harmonics thereof, and output means connected incircuit relation with the said oscillating circuit tofprovide a source'of 'current having a frequency equal to the' said arrangement adapted tobeenergimdbyasourceof alternating current comprising, in ,comhination, cuit including a condenser and coil wound upon a metio core and to oscillate freely at a and produce harmonics of the frequency, wherein the fundamental frequency is less than thefrequency of the an inductance ofone of 'said harmonics is equal to the frequency current to keep up the said harmonic thatv has a Vfrequency equal to the source of alternatingcurrent and to cause continuied oscillations of the fundamentall current at the fundamental frequency in the oscillating an oscillating cir-v alternating current, meansv adapted fundamental frequencyv said fundamental .15.

ma source oi 1. alternating current and wherein the frequency frequency of the/said i circuit. a rectiflen'and automatic switch means for momentarily connecting said rectifier in cirwinding on said magnetic core-to start free oscillations of the oscillating circuit at the said fundamental frequency and at reducing arrangement adaled cur- oneofsaidharmonics irequaltouierrequencycrtncsaidscurcecf saidoscillating circuitin circuit relation with thesaidsourceof upthesaidharmcsic `talfrequencyandofthesaldharmonicsinsald current, means for connecting' the alternating current tokeep 't matnusrrequencyequal thesaidsourceofalternatcurrentandtocausecontinued oscillations rfthefundsmental currentatthefundamental at the fundamental frequency at the harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequency of the said sourceof alter-` nating current and wherein the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuit in circuit relation with the said source of lalternating current to keep up the said harmonic that has a frequency equal to the frequency of the said in the 'oscillating circuit, means for connecting the non-linear irnpedance element in circuit relation with the said source of direct current to establish a direct current flux and for disconnecting the non-linear impedance element from circuit relation with the said source of direct current to cause the direct 4current iiux to collapse and induce a voltage in the nonlinear impedance tolstart free oscillations in the oscillating circuit at the said fundamental frequency and at the harmonics thereof, and out; put means connected in circuit relation, with the said oscillating circuit to provide a source of current having a frequency equal to the said fun- Y frequency equal' to the frequency of the said damental frequency, and reactance means connected in shunt circuit relation with the said condenser for fstabilizing the operation of the oscillating circuit.

6. Afrequency reducing arrangement adapted to be energized by a source of alternating 'current comprising, in combination, an oscillating circuit including a condenser and an inductance coil wound on an iron core and adapted to oscillate freely at a fundamental frequency and produce harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequency of the said source of alternating current and`wherein the frequency of one rdation with the said source 'of alternating current to keep up the said harmonic that has a an inductance Aalternating current and wherein a source of alternating cur` inductance and said trans; h

former to form two tuned circuits both adapted to oscillate freely at a fundamental frequency and produce harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequency of the said source of' the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuits in circuit relation with the said source of alternating current to keep up the said harmonic that has a frequency equal to the frequency of the said source of alternating current and to cause continued oscillations of the fundamental current at the fundamental frequency in the os` cillating circuits, a rectifier, switch means for momentarily connecting said rectifier in circuit lrelation with a winding on said iron core to start free oscillations in the oscillating circuits at the said fundamental frequency and at the harmonics thereof, and means for preventing radio inter--v ference during the operation of said switch, means.

8. A device for giving a source of modified current wherein the device is adapted to be energized by a source of alternating current comprising, in combination, a core, an inductance wound upon the core, a transformer, a condenser, connecting means interconnecting the core, the inductance, the transformer and `the condenser for forming two oscillating circuits at least one of which is adapted to oscillate freely at a fundamental frequency and produce harmonics of theA said fundamental frequency, wherein the funda- 'mental frequency is less than the frequency of the said source of alternating currentfand wherein the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillatingcircuits in circuit relation with the said` source of alternating current to keep up the said harmonic that has a frequency equal to the frequency of the said source of alternating current and to cause continued oscillations of the funda-- mental current at the fundamental frequency in the oscillating circuits, an output means comnected to a winding of said transformer, for supplying a reduced frequency current, another imductance connected in series with said condenser to control the high frequency voltage impressed upon said output means, a starting circuit including a protective device, a winding wound on .said core, and a rectifier connected to the sais! winding for starting oscillations in one of said oscillating circuits. a relay comprising a winding and contacts connected in said starting circuit for interrupting said starting circuit, a secondi winding on said relay connected ln series with.`

one of said oscillating .circuits for holding said relay operated. and instrumentalities connected to said relay contacts for suppressing radio frequency currents generated by the operation thereof. Y

9. A frequency 'reducing arrangement adapted to be energized by a source of alternating current comprising, in combination. an oscillati circuit including a condenser and an inductan wound on a core and adapted to o scillate freely at a fundamental frequency and produce harmonies of the said fundamental frequency, wherein the lfuntlarnental frequency is less than: the frequency of the said source of alternating current and wherein the frequency of one of saldi armonics is equal to the frequency of the said '40 bination of said auxiliary aoaaeie to keep up the said harmonic that has a freof alternating current quency equal to the'frequency ofthe said sourceof alternating current and to cause continued oscillations of the fundamental current at the means for starting free oscillations in the oscillating circuitat the said fundamental frequency and at the harmonics thereof, and output means connected across said condenser and a portion of the said inductance to provide a source .of

current having a frequency equal to the said .5 fundamental frequency. y

10. A frequency reducing arrangement adapted to be energized by a source of. alternating currentlcomprising, in combination, an oscillating circuit including a condenser and an inductance wound on a core and adapted to oscillate freely at a fundamental frequency and produce harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequency of the said source of alternating current and wherein the frequency of one of said harmonics is equal to the frequency of the said fundamental frequency in the oscillating circuit, J..

source of alternating current, means for cony necting the said oscillating circuit in circuit re'- lation with the said source of alternating current to keep up the said harmonic that has a fre quency equal to the frequency of the said source of alternating current and to caus continued oscillations of the fundamental current-at the fundamental frequency in the oscillating circuit, means for starting free oscillations 'in the oscillating circuit at the and at the harmonics thereof, an auxiliary inductance connected in series and output means connected to said series cominductanceand said condenser to provide a source of current-having a frequency equal to the said fundamental frequency. i

l1. A frequency reducing arrangement adapted 45 to be energized by a source of alternating current comprising, in combination, a core, an lnductance wound upon the core, a transformer, a condenser, connecting means interconnecting the core, the inductance, the transformer and the condenser i) for forming two oscillating circuits at least one of which is adapted to oscillate freely at a fundamental frequency and produce harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequency of 55 the said source of alternating current and wherein the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuits in circuit relation with the said source of 50 alternating current to keep up the said harmonic that has a frequency equal to the frequency of the said source of alternating current and vto'` cause continued oscillations of, the fundamental current at the fundamental frequency in the os-f' 65 cillating circuits, an output means connected to a winding of said transformer, another inductance connected'in series with said condenser to control the high frequency voltage impressed uponsaid output means, a starting circuit in- 70 cluding a protective device, a winding wound on .said core, and a rectifier connected thereto for starting oscillations in one of saidoscillating circuits.

12. A frequency reducing arrangement adapted 75 to be energized by a source of alternating current said fundamental frequencyv with said condenser,

,the oscillating circuits,

alternating current to keep the said fundamental adapted to oscillate comprising, in combination, a plurality of oscillating circuits each adapted to o scillate freely atl source of alternating current to keep up the said the freharmonic that has'a frequency equalto quency of the said source of valternating current and to cause continued oscillations of the fundamental current at the fundamental frequency in means for causing astart# ing current to flow inthe said oscillating circuits to start free oscillations in the said oscillating circuits at the said fundamental frequency and atthe harmonics thereof, and output means for providing a source equal to the said fundamental frequency.

13. A'frequency reducing arrangement adapted the said source of alter-- for connecting the said osof current having a frequency of alternating current and to be energized by a source of alternating current comprising, in combination, an oscillating circuit adapted to osclllate quency and'produce harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequencyof the said source of alternating. current and/ wherein the frequency of one of said harmonics is equal to the frequency of the said sourceof alternating current, means for connecting the said oscillating circuit in circuit relation with the said source of up the said harmonic that has a frequency equal to the frequency of the said `source of alternating current and to cause continued" oscillations of the fundamental current ati-the fundamental frequency in theoscillating circuit, means -for-1 causing a starting cur-- rent to flow in the said oscillatingcircuit to start freet oscilations inthe said oscillating circuit at frequency and at the harmonies thereof, and stabilizing means shunting aportion of said oscillating circuit to by-pas's a portion'of the .oscillating current from the said freely at a fundamentalu f reshunted portion of the said oscillating circuit, and

output meansfor providing 'a source of current having a frequency equal -to the said fundamental frequency.

14. A frequency reducing arrangement adapted to be energized by a source of alternating current comprising, in combinatioman oscillating circuit freely at a fundamental frequency andvpro'duceharmonlcs of the said fundamental frequency, whereinthe fundamental frequency is less than the frequency o f the said source of alternating current and wherein the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating. circuit in circuit relation with the said source of alternating current to that has a. vfrequencyequal to the frequency of the said source bf alternating current and to cause continued oscillations of the fundamental current at the fundamental frequency inthe oscillating circuit, starting means to establish a flux and to lcause the flux to collapse vfor causing a starting current to flow in the said oscillating circuit to start free oscillations. in the` said oscillating circuit'at the said fundamental frequency keep up the said harmonic and at the harmonics'thereof, means for ydelaying in the frequency o positive starting of the said oscillations, and stabilizing means shunting a portion of said oscillating circuit to by-pass a portion of the oscillating current from the said shunted portion of the said oscillating circuit, and output means for providing a source of current having a frequency equal to the said fundamental frequency.

15. A frequency reducing arrangement adapted to be energized by a source of alternating current comprising, in combination, an oscillating circuit adapted to oscillate freely at a fundamental frequency and produce harmonics of the said fundamental frequency, wherein the fundais less than the frequency of alternating current and where- Aone of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuit in circuit relation with the said source of alternating current to keep up the said harmonic that has a frequency equal to the frequency of the said source of alternating current and to cause continued oscillations of the fundamental current at the fundamental frequency in the oscillating circuit, startingmeans for causing a starting current to flow in the said oscillating circuit to start free oscillations in the said oscillating circuit at the said fundamental frequency and at the harmonics thereof, means for causing the starting means to operate repeatedly at delayed intervals to start the said free oscillations. and stabilizing means shunting a portion of said oscillating circuit to by-pass a portion of the oscillating current from .the said shunted portion of the said oscillating circuit, and output means for providing a source of current having a frequency equal to the said fundamental frequency. 16. A frequency reducing arrangement adapted to be energized by a source of alternating current 40 comprising, in combination, an oscillating cirsource of alternating Y current, means for connecting the said alternating current to cillating circuit, means for causing a starting .i

cuit adapted to oscillate frequency and produce fundamental frequency, frequency is less than freely at a fundamental harmonics. of the said wherein the fundamental the frequency of the said current and wherein the said harmonics is equal to said source of alternating frequency of one of the frequency `of the circuit in circuit relation with the said source of keep up the said harmonic vcurrent at the fundamental frequency in the oscurrent to now in the said oscillating circuit, to start free oscillations in the said oscillating circuit at the said fundamental frequency and at the harmonics thereof, and stabilizing means 00 shunting a portion of said oscillating circuit to 65 fundamental' u said fundamental by-pass a portion of the oscillating current from the said shunted portion of the said oscillating circuit, output means for providing a source of current having a frequency frequency, and inductance means associated with the oscillating circuit for causing an additional voltage to modify the wave 'form of the output voltage impressed upon the output means.

17. A frequency reducing arrangement adapted to be energized by a source of alternating current comprising. in combination, anoscillating circuit adapted to oscillate freely at a fundamental frequency and produce harmonics of the frequency. wherein 'the fundaoscillating equal to the saidY mental frequency is less than the frequency of the said source of alternating current and wherein the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuit in circuit relation with the said source of lalternating current to keep up the said harmonic that has a frequency equal to the frequency of the said source of alternating current and to cause continued oscillations of. the fundamental current at the fundamental frequency in the oscillating circuit, means for causing a starting current to flow in the said oscillating circuit to start free oscillations in the said oscillating circuit at the said fun amental frequency and at the harmonics thereof, and a transformer having one winding for shunting a portion of said oscillating circuit to by-pass a portion of the oscillating current from the said shunted portion of the said oscillating circuit and having another winding for supplying an output source of current having a frequency equal to the said fundamental frequency.

18. A frequency reducing arrangement adapted to be energized by a source of alternating cur-v rent comprising, in combination, lan oscillating circuit adapted to oscillate freely at a fundamental frequency 'and produce harmonics of the said fundamental frequency, wherein the fundamental frequency is less than the frequency of the said source of alternating `current and wherein the frequency of one of said harmonics is equal to the frequency of the said source of alternating current, means for connecting the said oscillating circuit in circuit relation with the said harmonics that has a frequency equal to the frequency of the said source of alternating current and to cause continued oscillations of the fundamental current at'the fundamental frequency in the oscillating circuit, means for causcircuit at the said fundamental frequency and at the harmonics thereof, a transformer having one winding for shunting a portion of said oscillating..circuit toqby-pass a portion of the oscilalternating current to keep up the lating current fromthe said shunted portion of rent having a frequency equal to the said funda the fundamental frequency isless than the fre.

alternating .current to keep up the said harmonic that hasa. frequency equal to the frequency of the said source of alternating current and to cause continued oscillations of the fundamental current at the fundamental fref quency in the oscillating circuit, means for starting free oscillations in the said oscillating circuit nsr at the said -fundamental frequencyiand at the harmonics thereof, a stabilizing transformerenergized by the oscillating circuit and arranged' to increase' the effective capacitive reactance of the condenser, and output means connected to the transformer for supplying an output current having a frequency equal to the said fundamental frequency. I 20. A frequency reducing arrangement adapted to be energized by a source of alternating current comprising, in combination, aflrst oscillating circuit adaptedv to oscillate freely at a first fundamental frequency and produce harmonics l of the said first fundamental frequency, wherein the said first fundamental frequency is less than the frequency of the said source. of alternating current and wherein the frequency of one of said harmonics of the first fundamental frequency is equal to the frequency of the said source of al. ternating current, means for connecting the said oscillating circuit in circuit relation with the'said source of alternating current to keep up the said harmonic of the said first fundamental frequency that has a frequency equal to the frequency of the said source of alternating current and to *cause continued oscillations of the rst funda-- mental current at the first-fundamental frequency in the oscillating circuit, a second oscillating circuit associated with the first oscillatingcircuit and adapted4 to oscillateA freely at va sec,- ond fimdamental frequency and produce, harmonies of the said second fundamental frequency,

wherein the second fundamental frequency. is

' the other side of the capacitorto the source of alternating current, circuit connection for con.

less than the frequencyof the said first fundamental frequency and wherein the-frequency of one of said harmonics of the :second fundamental frequency is equal vto the frequency of the said first fundamental frequency, meansfor starting the oscillations of the said oscillating circuits,

. 40'and output means for providing a source of ,cur-

rent having Aa frequency equal to the said second fundamental frequency.

21. In combination, an oscillating'` circuit. -means for causing an oscillating current tn ow v inthe oscillating circuit, stabilizing means shunting a portion of said oscillating circuit to by-pass a portion of the oscillating current from the said shunted portion of the said voscillating circuit, and output means energized by the oscillating circuit. said output means providing an output current having 'a frequency equal to the frequency of the oscillating current in the oscillating cire cuit.

22. In combination.' an oscillating circuit'in- 55 cluding a non-linear impedance and a capacitor,

means for causing an' oscillating current to Ailow in the oscillating circuit, stabilizing means connected in shunt circuit relation with the capacitor, and output means energized by the oscillating 00 circuit, said output means .providing a source of current having a frequency equalto the frequency of the oscillating current in the oscillating. circuit.

23. In combinationf'an' oscillating circuit in-r.

cluding a non-linear impedance anda capacitor, means for causing an oscillating current to flow in. the oscillating circuit., and' a stabilizing output transformer shunting the. capacitor Vand energized by the oscillating circuit, said transformer 70 providing an output current having a frequency equal to the frequency of the'oscillating current`. 24. In combination, an oscillating circuit in- ,i cluding a non-lineariimpedance and a capacitor, means for causing an oscillating current to flow in the oscillating circuit, and a' stabilizing output. .i

/transformer having 'one winding shunting the capacitor and energized by the oscillating circuit and having another winding for'supplying an output current having a frequency equal to the frequency of the oscillating current. 1 y

25.. In combination, an oscillating circuit including a nonlinear impedance and a `capacitor, meansfor causing an oscillating current to eflow in the oscillating circuit, anda stabilizing output transformer energized by the oscillating circuit and varranged to increase the effective capacitive reactance of the capacitor,

26. In combination, an oscillating cluding a non-linear impedance and a capacitor.' means for causing oscillating current to -flow in the oscillating circuit, and a stabilizing 011tput transformer shunting the capacitor. and energized by the oscillating circuit for providing an circuit ni-V l output current having 'a frequency equal to the` frequency of the oscillating current, and inductance means connected i'n circuit relation with the transformer to cause an additional voltage to'v modify-the wave form ofthe outputI voltage of the transformer. V

27. -A frequency reducing arrangement adapted to be energized by a source of alternating 'current'.

comprising, in combination, a non-linear im'- pedance, a capacitor, a stabilizing impedance, circ'uit connection for connecting one 'side ofthe non-linear impedanceto one side of/the capacitor,

circuit connection for connecting the other side of the non-linear impedance to th'source of alternating. current, circuit connection for connecting necting the stabilizing' impedance in shunt with the capacitor, means for starting an oscillating `a capacitor, a ,stabilizing transformer having -a primary winding with'an intermediate tap and a secondary winding, circuit connection for con'- necting one side of the non-linear'lmpedance to the intermediate tap of the primary windingof,

the transformer, circuit connection for connecting the other side-of the non-linear impedance to the alternating current connection for connecting one side of the primary winding to the alternating current supply source,

Supply source.V circuit' circuit connection for connecting the capacitor inl i shunt with the primary winding of lthe transformer, and means fo'r starting an oscillating current in the non-linear impedance, the capacitor,

the primary winding of the transformer and the circuit connections associated therewith to f proprimary winding with an intermediate tap and al secondary winding, circuit connectionfor connecting one side of the no n-linear impedance to .the intermediate tapyof the primary winding of the transformer, circuit connection forconnecting the other side of the non-linear impedance to duce an output current in the secondary winding nsl the alternating current supply source, circuit connection for connecting one side of the primary winding to the alternating current supply source, circuit connection for connecting the capacitorin shunt with the primary winding of the transformer, means for-starting an oscillating current in the non-linear impedance, the capacitor, the primary winding of the transformer and the circuit connections associated therewith to produce an output current in the secondary winding hav- Ving a frequency equal to the frequency of the oscillating current. and yinductance means connected in sexies with the capacitor and'the pri, mary winding of the transformer to cause an additional voltage to modify the wave form of the output voltage of the transformer.

30. In combinationl a transformer having a secondary winding and a primary winding having an intermediate tap.4 a plurality 'of oscillating circuits having connections connected respectively to the two sides and the intermediate `tap of the primary winding ofthe transformer. the said secondary winding 'being adapted to deliver ya current having a frequency equal to the frequency of the oscillating current oi' the oscillating circuits. f

31. In an electrical oscillatingtsystem adapted to energize a variable electrical load varying inay range between substantially no-load to full-load, in combination. an oscillating circuit having a l wide variations of the non-linear impedance. wherein .the ouillating circuit becomes detuned by changeable values of the oscillating current, output connection means connected to the oscillating circuit forsupplying the variable electrical load throughout the rangeA from substantially no-load to full-load. thereby urllng'the oscillating rcurrent to varying in accordance with changes in the electrical load ,and tending to cause detuning of the oscillating circuit, and stabilizing means responsive to the variable load condition for giving stability to the tuning. n

, 32. An electrical system adapted to be enersised by an alternating current variable voltage supply source and arranged to deliver a substantially constant output voltage comprising, in combination, an oscillating current including a nonlinear inductance element and a capacitor adapted to be energised by the said supply source, and arranged to resonate at a frequency lower than the frequency of the supply source, and stabilizing means shunting the capacitor to by-pass a portion of the oscillating current around the capacitor and stabilizing the voltage across the capacitor, and output means connected in circuit relation with the capacitor of the oscillating circuit, said output means being adapted to deliver a substantially constant output voltage for relative voltage of the supply source. CLOSMAN P. BTOCKER. 

